QUIGS: PAGES-PMIP Working Group on Quaternary Interglacials: Interglacial intensity
Date: 19-22 September 2023
Location: Grenoble, France
Venue: Grenoble University Campus (details to follow)
Over the last few years, the successive PAGES Working Groups (WG) of PIGS and QUIGS have made significant advances in our understanding of past interglacials in terms of factors controlling their occurrence, duration and internal variability, and have also provided new insights into periods of excess warmth that can potentially inform future climate changes.
The topic of this workshop will be on the intensity of past interglacials with particular foci on:
1. Past interglacials that do not fit neatly into the astronomical theory of ice age.
We aim to tackle the following topics:
The MIS 11c interglacial is characterized by its long duration, high sea level, and persistence of high atmospheric CO2 concentrations. The strong climatic response is often considered paradoxical because it was attained under weak summer insolation forcing. The weak forcing led to a slow but steady loss of ice volume, that was sufficient to allow ocean outgassing of CO2, but insufficient to raise sea level within a single precessional cycle. This gave rise to a prolonged interval with large residual ice sheets and high CO2 concentrations. Despite accumulating evidence, we still need to constrain the precise timing and rate of the sea level rise during the Termination V and the strength of the Atlantic Meridional Overturning Circulation (AMOC) in order to explore two alternative scenarios:
(i) is high atmospheric CO2 concentration at the beginning of MIS 11 compatible with large residual ice sheets persisting in the Northern Hemisphere?; or
(ii) is high CO2 concentration by itself enough to melt northern ice sheets, despite the weak insolation forcing and a weak AMOC?
In addition, we still need to understand:
- Why is there no significant reduction in CO2 or sea level in the first insolation minimum.
- What was the character of the responses of temperature and the hydrologic cycle during MIS 11c?
- What was the character of abrupt climate variability during MIS 11c?
- How special is MIS 11 in the context of the interglacials of the past 800 kyr?
While we expect a strong focus on MIS 11, contributions on other individual interglacials as well as comparisons between multiple interglacials are welcome.
Note that while we expect to consider the LIG as a basis for comparison with other interglacials, it is not our intention to revisit what we know about the LIG as previous QUIGS workshop focused on this topic.
2. Long-term changes in interglacial intensity over the past 800 kyr
We expect to look into different metrics of intensity (e.g. temperature, GHG, sea level highstand) and into the change in interglacial intensity before and after the Mid-Brunhes event. Contributions could tackle at least one of the following questions:
- How does the intensity of past interglacials depend on the region and the climate tracers being considered?
- What causes the higher concentrations in GHG in post-MBE interglacials compared to pre-MBE interglacials?
- What was the climatic effect of differences in atmospheric CO2 of ~40-50 ppm between interglacials?
- What controls the intensity of past interglacials?
- Can we predict based on insolation changes, the intensity of interglacials of the last 800 kyr?
A detailed program will be released soon.
On 21 September, we plan to have an excursion in the Grenoble area to explore the geomorphological and sedimentological records of the glacial-interglacial cycles of the past 300 ka.
Details will be provided as soon as these are available.
If you are interested, please email the organizing committee (details below) before 31 March with a short letter of intention and a description of the work you would like to present.
We'll proceed to the selection of participants shortly afterwards and notice for participations will be given by mid-April 2023.
We welcome applications from scientists from the data and modelling communities working on these areas.
We have some financial support available for Early-Career Scientists as well as scientists from developing countries.
For further information, please contact the organizing committee members (see email addresses above).
Note that there is an on-going discussion amongst QUIGS members regarding the setting-up of coordinated equilibrium climate model experiments on MIS 11. If you'd like to join that discussion, please let us know.